Duct adaptors



v June 17, 1969A P. A. wlLKlNs DUCT ADAPTORS l Sheet Filed June 23, 1967 lul/emma: @HMP AWMR MLMIMS KWS* Kw P. A. WILKINS v DUCT ADAPTORS June 17, 1969 Sheet Z @f2 Filed June 25, 1967 M.. O l

4i. #i 111. ,lill

United States Patent O U.S. Cl. 126--307 9 Claims ABSTRACT F THE DISCLOSURE This specification discloses an adaptor for concentric ducts, the `adaptor comprising a two-part box, the parts of which may be assembled in two different positions to allow for two different orientations of the ducts leaving the adaptor,- which orientations may be at right angles. The adaptor is described as connecting a gas heater to a balanced flue.

BACKGROUND OF INVENTION Field of the invention The invention is applicable to concentric ducts and a common application is in a balanced flue where the products of combustion from a burner pass to a flue terminal along, for example, an inner duct arranged within :an outer duct which leads combustion air to the burner. The adaptor may be used in other circumstances where similar problems arise with concentric ducts. By concentric as used herein I mean that one of the ducts is located, at least over part of its length, within the other duct and I do not mean that the ducts necessarily have a common centre line or axis.

In small domestic gas-buming heaters it is now becoming common to use a balanced flue and it is often necessary to provide two alternative positions on the heater to which the flue can be connected. These two positions are normally at right angles. For example if the heater is secured to a wall then it may be desired either to take the flue directly through the wall behind the heater or it may be desired to take the flue along the first wall to which the heater is fixed, fand through, for example, another wall at right angles to the first wall. It is therefore necessary to provide an adaptor for the flue so that the flue terminal can be connected to either of the two alternative positions.

Description of the prior art One known adaptor comprises a generally cubical box having an inlet in one wall thereof and two alternative outlets in two other and adajacent walls, the outlets being provided with knock-out panels so that either can be used with a first or outer duct. Within the outer box there is an inner box connected to a second or inner duct which in turn passes through another wall of the outer box. The inner box lalso has two outlets with knock-out panels which are in alignment with the knock-out panels in the walls of the outer box. To use the adaptor, the corresponding knock-out panels are removed from the inner and outer boxes and ducts are connected to the outlets rendered effective by removal of the knock-out panels and the ducts in turn are connected to a flue terminals.

Boxes of this type are expensive to produce and it is an object of the present invention to provide a cheap and simple adaptor in which knock-out panels may be eliminated or reduced in number as compared with the known type of adaptor described above.

ice

SUMMARY oF THE INVENTION According to the invention, we provide an adaptor for concentric ducts comprising a two-part box, one part providing a first port for connection to the outer duct and the other part a second port for connection to said outer duct, the parts of the box having mating surfaces such that the parts can be assembled to form the box with said surfaces in contact in two different relative positions to provide two different relative positions of the first and second ports, an aperture being provided in the box wall for the inner duct, the -aperture being formed half in the one part of the box and half in the other part thereof.

With this arrangement, it is in many embodiments unnecessary to provide any knock-out panels since the first and second ports can be arranged to occupy either of their two alternative relative positions by assembling the box parts in a different manner. In use the inner duct is closely received in the aperture and passes through one of the first and second ports with clearance. Preferably the second duct includes a pipe in the form of an elbow, one limb thereof being received in the aperture and the other limb thereof terminating within the box and being connected to a further portion of the second duct which passes through said one port. The pipe is arranged so that it can be set during assembly of the parts of the box so that said other limb faces the port required. The pipe may be rotated about the axis of the aperture to set said other limb in the desired position.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in detail by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective View, with a duct adaptor exploded away, showing a duct adaptor embodying the invention applied to a gas-red heater as shown in outline;

FIGURE 2 is a detail view of the duct adaptor of FIG- URE 1 shown exploded away and in a second position;

FIGURE 3 is a section through the duct adaptor in the position of FIGURE 2 and showing it connected to a balance flue terminal.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGURE 1, the assembly thereshown comprises a gas-fired room heater indicated generally at 10 having a gas burner 11 therein. A cross-flow fan 12 is driven by an electric motor 13 for passing air over a heat exchanger within ra casing 14 and forming part of the heater. Also driven by the motor 13 is a further fan within a casing 15 which is arranged to deliver air along a duct 16 to an inlet 17 in the heat exchanger to provide combustion air for the burner 11. The inlet 18 to the casing 15 and the outlet from the heater are connected to a balanced flue terminal 19 as show in FIG- URE 3.

Referring now to FIGURE 1, the inlet 18 to the casing 15 is connected to one part 20 of 'a two-part box, the other part of which is indicated -at 21, the parts 20 and 21 when connected together providing a duct adaptor. The part 20 has an upper wall 22, 4a lower wall 23 and side wall 24 and 25, the box part being generally triangular in plan view. The inlet 18 to the casing 15 is formed in the wall 25 `and is provided 'by a part 26 of the duct 16 which is flanged over the edge of an aperture in the wall 25.

The free edges of the walls 22, 23, 24 and 25 are provided with flange means comprising two generally U- shaped flanges 27 Iand 28. The flanges are spaced apart in the upper wall 22 -by means of a half-circular aperture 29 formed in said wall. Similarly, the anges are spaced apart by a similar aperture formed in the lower wall 23. The apertures 29 and 30 are in alignment with one another and are both the same size and are semi-circular.

Referring now to the box part 21, this has an upper wall 31, twoy side walls 32 and 33 and a lower wall 34. The box part 21 is formed with two U-shaped flanges and 36 which are arranged to mate with the U-shaped flanges 27 and 28. The vflanges 36 and 35 are interrupted by a semi-circular aperture 37 in the top wall 31 and there is a similar semi-circular aperture, not shown, in the wall 34 and which is in alignment with the aperture 37. The flanges 27 and 28 lie in a plane and the anges 35 and 36 lie in a plane. The flanges 27 and 28 are similar as are the flanges 3S and 36. The box parts can thus be assembled by bringing the ange 35 into contact with the flange 27 and by bringing the flange 36 into contact with the flange 28 and by passing screws through aligned holes 38 in the mating flanges. With the box parts assembled as described above, a port 39 in the wall 33 of the box part 21 will be located as shown in FIGURE 1 and will be alignment with a port 39a in the wall 25 which leads to the casing 15. The apertures 29 and 37 will co-operate to form ya circular aperture in the top of the box and the aperture 20 and the corresponding aperture in the lower wall 34 of the box part 21 will also cooperate to form a circular aperture in the bottom of the box. Immediately below said aperture, and in alignment therewith is located the upper end 40 of a swan-necked fitting 41 of a ue gas duct, the other end 42 of which is connected to the heat exchanger within the casing 14 to lead off the products of combustion of the burner 11. Received in the upper end 40 of the member 41 is an elbow indicated generally at 43 having a lower end 44 received in the aperture in the lower wall of the -box and rotatable in the upper end 40 of the member 41; the elbow has an upper end 45. As shown in FIGURE l, the upper end 45 is directed towards the port 39 in the box part 21. It follows that a pipe can be pushed through the port 39 to engage the upper end 45 of the elbow 43, the pipe being received with clearance in the port 39 and a second pipe can then be fitted onto the flange 46 of the port 39 as will hereinafter be described.

Referring to FIGURES 2 and 3, the box parts 20 and 21 can be assembled in a second relative position as shown in FIGURE 2 in which the flange 35 is brought into contact withf'the flange 27. In this relative position, the port 39 is at right angles to the port 39a in the wall 25 of the box part 20. In this position, therefore, the elbow 43 has -been turned so that its upper end 45 is in alignment with the port 39.

An installation of the heater will now be described with reference to FIGURES 2 and 3. The heater is located against al wall 47 shown in FIGURE 3 with its longitudinal dimension A shown in FIGURE l parallel to the surface 48 of the wall and it is desired to take the balanced flue through the -wall immediately behind the heater. For this purpose, the duct adaptor is assembled as shown in FIGURE 2 with the port 39 at right angles t0 the port 39a so that, as shown in FIGURE 3, the port 39 faces the surface 48 of the wall 47. The box part 20 is fixed to the heater and when the heater has been fixed to the wall, the elbow 43 is turned so that its upper end 45 faces the port 39 as shown in FIGURE 3 and so that its lower end 44 is journalled in the upper end 40 of the swan-necked fitting 41. The box part 21 is then fixed in position as described above. The circular aperture formed in the lower walls 23 and 34 of the box parts 20 and 21 when they are assembled 'by the semi-circular aperture 30 in the wall 23 and the corresponding aperture in the wall 34 closely grip the lower end 44 of the elbow 43. The circular aperture which is provided in the upper walls 22 and 31 of the box parts when they are assembled is closed by means of a circular plate 149 having a flange thereon which is a close fit in the circular aperture referred to.

The box 20, 21 is then connected to the balanced tiue -fitting 19 by means of an outer pipe 49 which is received Within the flange 46 and which is also received within an outer pipe '50 connected to the balanced ue terminal. The elbow 43 receives an inner pipe 51 which is received within a further pipe 52 which is also connected to the flue terminal 19. The pipe 52 terminates between the plates 53 and 54 of the terminal and is open at 56 between said plates. The pipe 50 terminates at a further plate 57 which supports the plates 53 and 54 on pins 58.

The heater operates as follows, air for combustion enters the open end 59 of the pipe 50, flows along the pipe 49 and into the box 20, 21 through the port 39. The air then passes through the port 39a and along the duct 16 to the combustion air inlet 17 and supports the combustion of the burner 11.

The products of combustion from the burner 11 pass to the top of the heat exchanger and then into the swannecked fitting 41, the elbow 43, and the pipes 51 and 52 to flow out of the fiue terminal at 56.

It will be seen that the box part 20 comprises a port 39a for connection to one part 16 of an outer duct which duct may be considered to be the duct 16 and the pipes 49 and 50. The other box part 21 comprises a second port 39 for connection to the outer duct by way of the pipe 49. The inner duct comprises the swan-necked fitting 41, the elbow 43 and the pipes 51 and 52 and this inner duct lies, at least partly within the outer duct and is therefore concentric with the outer duct in the sense defined above.

As has been described in detail above, the heater can be installed with the port 39 at right angles to the port 39a as shown in FIGURES 2 and 3. However, in some circumstances, it may be desired to arrange the heater against the surface of one wall and to carry the flue out through a wall at right angles to the one wall. In this case, the box 20, 21 is assembled as shown in FIGURE 1 with the port 39 in alignment with the port 39a and with the elbow 43 having its upper end 45 directed towards the port 39. The box and the elbow 43 will then be connected to a balanced flue terminal in the same manner as has been described with reference to FIGURE 3.

It will be seen that a heater may be supplied with a duct adaptor as described above and can then be connected into a location in either of the two possible positions without it being necessary to determine beforehand which position is to be adopted. This arrangement considerably simplifies the installation of the heater. Moreover, the box parts may be comparatively cheaply made from sheet metal having the flanges 27, 28, 35 and 36 stamped in one piece with the box parts.

In a further arrangement the box part 20 could be formed without the aperture 29 in the upper wall 22 thereof so that rather than use a circular blanking plate 149 as shown in FIGURE 2, a half-circular plate would be used.

In a still further arrangement, the box part 21 could be formed with knock-out panels in the semi-circular recess 37 and the corresponding recess in the lower wall 34 so that it will be unnecessary to use a blanking plate such as the plate 149 at all since only the knock-out panel for the semi-circular aperture which was required to pass the swan-necked fitting 41 would be formed by removal of the knock-out panel.

Although the invention finds particular application in the connection of a heater to a balanced flue terminal, it will be appreciated that it could also be used whether two concentric ducts have to be connected in either of two alternative positions. The adaptor is particularly useful in connection with the heater described in patent application Ser. No. 566,294, filed July 19, 1966 by Philip Arthur Wilkins and Royston Aubrey Chadbourne.

I claim:

1. An adaptor inner and outer concentric ducts, the adaptor comprising a two-part box, one part having a first port for connection to the outer duct and the other part having a second port for connection to said outer duct, the parts of the box having means forming mating surfaces such that the parts can be assembled to form the box with said surfaces in contact in two different relative positions to provide two different relative positions of the irst and second ports, an aperture being provided in the box wall for the inner duct, the aperture being formed half in theone part of the box and half in the other part thereof.

2. An adaptor according to claim 1 wherein the inner duct is closely received in the aperture and passes through one of the rst and second ports with clearance.

3. An adaptor according to claim 2 wherein the inner duct includes a pipe in the form of an elbow, one limb thereof being received in the aperture and the other limb thereof terminating within the box and being connected to a further portion of the inner duct which passes through said one port.

4. An adaptor according to claim 3 wherein said pipe may be rotated about the axis of the aperture so as to set said other limb in the desired position.

5. An adaptor according to claim 1 wherein each of the parts of the box is provided with two half-apertures in opposite Walls arranged so that in each of the two relative assembled positions of the box parts there are two aligned apertures, one in each of said opposite walls, one of said apertures receiving the inner duct and the other being provided with a blanking plate.

6. An adaptor according to claim 1 wherein one of the parts of the box is xed in position and provided With one half-aperture, the other part of the box being provided with two knock-out panels which are in opposite walls and removable to provide half-apertures so that whichever half-aperture in said other part is required when the adaptor is assembled may be formed by removing the appropriate knock-out panel.

7. An adaptor according to claim 1 wherein the mating surface of each part lies in a plane.

8. An adaptor according to claim 7 wherein the mating surfaces lie on flanges of the box parts.

9. An assembly of a heating device with a balanced ue, the balanced ue including a duct adaptor as claimed in claim 1.

References Cited UNITED STATES PATENTS 2,695,016 11/1954 Miller et al. 2,709,999 6/ 1955 `Nagel 126-307 2,755,794 7/ 1956 Wendell 98-62 FREDERICK L. MATTESON, JR., Primary Examiner. E. G. FAVORS, Assistant Examiner.

U.S. Cl. X.R. 285-133 

